No one has claimed responsibility for Monday's deadly violence, which comes as Iraq faces growing sectarian tensions after months of Sunni-led anti-government protests against the Shi'ite-run government.

Iraq's Sunni minority has accused the ruling Shi'ites of targeting them for arrests and marginalizing them politically.

Bombings and other violence have killed hundreds in Iraq this month.

Last week, U.S. Vice President Joe Biden telephoned Iraqi Prime Minister Nouri al-Maliki to express concern over the recent rise in violence, including bombings.

The White House says Biden pledged continued U.S. support for Iraq in its fight against terrorism.